A New Species of Modelling System

Modelling, rather than solution, support is generally recognizedas a critical problem area inhibiting far greater use of mathematicalprogramming. This paper makes use of spreadsheets to proposea new species of (mathematical programming dependent) modellingsystem which could overcome that inhibition     

IS THERE UNIT ROOT IN THE NITROGEN OXIDES EMISSIONS: A MONTE CARLO INVESTIGATION?

Abstract Use of the time‐series econometric techniques to investigate issues about environmental regulation requires knowing whether air pollution emissions are trend stationary or difference stationary. It has been shown that results regarding trend stationarity of the pollution data are sensitive to the methods used. I conduct a Monte Carlo experiment to study the size and power of two unit root tests that allow for a structural change in the trend at a known time using the data‐generating process calibrated to the actual pollution series. I find that finite sample properties of the Perron test are better than the Park and Sung Phillips‐Perron (PP) type test. Severe size distortions in the Park and Sung PP type test can explain the rejection of a unit root in air pollution emissions reported in some environmental regulation analyses.     

利用旋转磁场驱动电流技术产生和维持FRC的实验

利用旋转磁场驱动电流技术产生场反向磁场位形(FRC)。实验中未观察到任何等离子体不稳定性。FRC的寿命由所加旋转磁场的时间(40ms)决定。 关键词：